/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// gl_warp.c -- sky and water polygons

//#define NO_PNG
#ifndef NO_PNG
#include <png.h>
#endif

#include "quakedef.h"

extern	model_t	*loadmodel;

int		    skytexturenum;
int		    solidskytexture;
int		    alphaskytexture;
float	    speedscale;		// for top sky and bottom sky

msurface_t	*warpface;

void BoundPoly (int numverts, float *verts, vec3_t mins, vec3_t maxs)
{
    int		i, j;
    float	*v;

    mins[0] = mins[1] = mins[2] = 9999;
    maxs[0] = maxs[1] = maxs[2] = -9999;

    v = verts;

    for (i=0 ; i<numverts ; i++)
    {
        for (j=0 ; j<3 ; j++, v++)
        {
            if (*v < mins[j])
            {
                mins[j] = *v;
            }

            if (*v > maxs[j])
            {
                maxs[j] = *v;
            }
        }
    }
}

void SubdividePolygon (int numverts, float *verts)
{
    int		    i, j, k;
    vec3_t	    mins, maxs;
    float	    m;
    float	    *v;
    vec3_t	    front[64], back[64];
    int		    f, b;
    float	    dist[64];
    float	    frac;
    glpoly_t	*poly;
    float	    tex[2];

    if (numverts > 60)
    {
        Sys_Error ("numverts = %i", numverts);
    }
    BoundPoly (numverts, verts, mins, maxs);

    for (i=0 ; i<3 ; i++)
    {
        m = (mins[i] + maxs[i]) * 0.5;
        m = gl_subdivide_size.value * floor (m / gl_subdivide_size.value + 0.5);
        if (maxs[i] - m < 8) continue;
        if (m - mins[i] < 8) continue;

        // cut it
        v = verts + i;

        for (j=0 ; j<numverts ; j++, v+= 3)
        {
            dist[j] = *v - m;
        }

        // wrap cases
        dist[j] = dist[0];
        v-=i;
        VectorCopy (verts, v);

        f = b = 0;
        v = verts;

        for (j=0 ; j<numverts ; j++, v+= 3)
        {
            if (dist[j] >= 0)
            {
                VectorCopy (v, front[f]);
                f++;
            }
            if (dist[j] <= 0)
            {
                VectorCopy (v, back[b]);
                b++;
            }

            if (dist[j] == 0 || dist[j+1] == 0) continue;

            if ( (dist[j] > 0) != (dist[j+1] > 0) )
            {
                // clip point
                frac = dist[j] / (dist[j] - dist[j+1]);

                for (k=0 ; k<3 ; k++)
                {
                    front[f][k] = back[b][k] = v[k] + frac*(v[3+k] - v[k]);
                }
                f++;
                b++;
            }
        }
        SubdividePolygon (f, front[0]);
        SubdividePolygon (b, back[0]);
        return;
    }
    poly = Hunk_Alloc(sizeof(glpoly_t));
    poly->next = warpface->polys;
    warpface->polys = poly;
    poly->numverts = numverts;
    poly->firstvertex = R_GetNextVertexIndex();

    for (i=0 ; i<numverts ; i++, verts+= 3)
    {
        tex[0] = DotProduct (verts, warpface->texinfo->vecs[0]);
        tex[1] = DotProduct (verts, warpface->texinfo->vecs[1]);

        //Penta: lighmap coords are ignored...
        R_AllocateVertexInTemp(verts, tex, tex);
    }
}

/*
================
GL_SubdivideSurface

Breaks a polygon up along axial 64 unit
boundaries so that turbulent and sky warps
can be done reasonably.
================
*/
void GL_SubdivideSurface (msurface_t *fa)
{
    vec3_t		verts[64];
    int			numverts;
    int			i;
    int			lindex;
    float		*vec;

    warpface = fa;

    //
    // convert edges back to a normal polygon
    //
    numverts = 0;

    for (i=0 ; i<fa->numedges ; i++)
    {
        lindex = loadmodel->surfedges[fa->firstedge + i];

        if (lindex > 0)
        {
            vec = loadmodel->vertexes[loadmodel->edges[lindex].v[0]].position;
        }
        else
        {
            vec = loadmodel->vertexes[loadmodel->edges[-lindex].v[1]].position;
        }
        VectorCopy (vec, verts[numverts]);
        numverts++;
    }
    SubdividePolygon (numverts, verts[0]);
}

//=========================================================

// speed up sin calculations - Ed
float	turbsin[] = {
#include "gl_warp_sin.h"
};
#define TURBSCALE (256.0 / (2 * M_PI))

/*
=============
EmitWaterPolys

Does a water warp on the pre-fragmented glpoly_t chain
=============
*/
void EmitWaterPolys (msurface_t *fa)
{
    glpoly_t	*p;
    float		*v;
    int			i;
    float		s, t, os, ot;

    for (p=fa->polys ; p ; p=p->next)
    {
        glBegin (GL_TRIANGLE_FAN);

        for (i=0, v=(float *)(&globalVertexTable[p->firstvertex]) ; i<p->numverts ; i++, v+=VERTEXSIZE)
        {
            os = v[3];
            ot = v[4];

            s = os + (turbsin[(int)((ot*0.125+realtime) * TURBSCALE) & 255]) * 0.25;
            s *= (1.0/64);

            t = ot + (turbsin[(int)((os*0.125+realtime) * TURBSCALE) & 255]) * 0.25;
            t *= (1.0/64);

            glTexCoord2f (s, t);
            qglMultiTexCoord2fARB (GL_TEXTURE1_ARB, s, t);
            glVertex3f (v[0], v[1], v[2]);
        }
        glEnd ();
    }
}

float RandomXY(float x, float y, int seedlike)
{
    float ret;
    int n = (int)x + (int)y * seedlike;
    n = (n << 13) ^n;
    ret = (1 - ((n * (n * n * 19417 + 189851) + 4967243) & 4945007) / 3354521.0);
    return ret;
}

void EmitMirrorWaterPolys (msurface_t *fa)
{
    glpoly_t	*p;
    float		*v;
    int			i;
    float		s, t, os, ot;

    for (p=fa->polys ; p ; p=p->next)
    {
        glBegin (GL_TRIANGLE_FAN);

        for (i=0, v=(float *)(&globalVertexTable[p->firstvertex]) ; i<p->numverts ; i++, v+=VERTEXSIZE)
        {
            os = v[0];
            ot = v[1];

            //Fake the tex coords a bit so it looks a bit like water
            s = RandomXY(os,ot,57)*turbsin[(int)((ot*0.125+realtime) * TURBSCALE) & 255];
            s *=0.25;
            t = RandomXY(os,ot,63)*turbsin[(int)((ot*0.125+realtime) * TURBSCALE) & 255];
            t *=0.25;

            glTexCoord3f (v[0]+s, v[1]+t, v[2]);
            glVertex3f (v[0],v[1],v[2]);
        }
        glEnd ();
    }
}

/*
=============
EmitMirrorPolys
=============
*/
void EmitMirrorPolys (msurface_t *fa)
{
    glpoly_t	*p;
    float		*v;
    int			i;

    for (p=fa->polys ; p ; p=p->next)
    {
        glBegin (GL_TRIANGLE_FAN);

        for (i=0, v=(float *)(&globalVertexTable[p->firstvertex]); i<p->numverts ; i++, v+=VERTEXSIZE)
        {
            qglMultiTexCoord2fARB(GL_TEXTURE1_ARB, v[3]/64, v[4]/64);
            glTexCoord3fv(v);
            glVertex3fv(v);
        }
        glEnd ();
    }
}

/*
=============
EmitSkyPolys
=============
*/
void EmitSkyPolys (msurface_t *fa)
{
    glpoly_t	*p;
    float		*v;
    int			i;
    float	s, t;
    vec3_t	dir;
    float	length;

    for (p=fa->polys ; p ; p=p->next)
    {
        glBegin (GL_TRIANGLE_FAN);

        for (i=0,v=(float *)(&globalVertexTable[p->firstvertex]) ; i<p->numverts ; i++, v+=VERTEXSIZE)
        {
            VectorSubtract (v, r_origin, dir);

            dir[2] *= 3;	// flatten the sphere

            length = dir[0]*dir[0] + dir[1]*dir[1] + dir[2]*dir[2];
            length = sqrt (length);
            length = 6*63/length;

            dir[0] *= length;
            dir[1] *= length;

            s = (speedscale + dir[0]) * (1.0/128);
            t = (speedscale + dir[1]) * (1.0/128);

            glTexCoord2f (s, t);
            glVertex3fv (v);
        }
        glEnd ();
    }
}

/*
===============
EmitBothSkyLayers

Does a sky warp on the pre-fragmented glpoly_t chain
This will be called for brushmodels, the world
will have them chained together.
===============
*/
void EmitBothSkyLayers (msurface_t *fa)
{
    GL_DisableMultitexture();

    GL_Bind (solidskytexture);
    speedscale = realtime*8;
    speedscale -= (int)speedscale & ~127 ;

    EmitSkyPolys (fa);

    glEnable (GL_BLEND);
    GL_Bind (alphaskytexture);
    speedscale = realtime*16;
    speedscale -= (int)speedscale & ~127 ;

    EmitSkyPolys (fa);
}

/*
=======================================================================================================

SKYBOX

=======================================================================================================
*/

#define SKY_TEX 10000
char	    skybox_name[64];
float       skybox_cloudspeed;
qboolean    skybox_hasclouds;

/*
==================
R_LoadSkys
==================
*/
char	*suf[7] = {"rt", "bk", "lf", "ft", "up", "dn","tile"};
void R_LoadSkys (void)
{
    int		i;
    char	name[64];

    skybox_hasclouds = true;

    for (i=0 ; i<7 ; i++)
    {
        sprintf (name, "env/%s%s.tga", skybox_name, suf[i]);

        if (!Image_LoadTexture(name, 4))
        {
            if (i == 6)
            {
                skybox_hasclouds = false;
            }
            else
            {
                Con_Printf ("Couldn't load %s\n", name);
            }
            continue;
        }
        else
        {
            GL_Bind (SKY_TEX + i);
            glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA, image_width, image_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image_rgba);

            free (image_rgba);

            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
        }
    }
}


vec3_t	skyclip[6] =
{
    {1,1,0},
    {1,-1,0},
    {0,-1,1},
    {0,1,1},
    {1,0,1},
    {-1,0,1}
};

// 1 = s, 2 = t, 3 = 2048
int	st_to_vec[6][3] =
{
    {3,-1,2},
    {-3,1,2},

    {1,3,2},
    {-1,-3,2},

    {-2,-1,3},		// 0 degrees yaw, look straight up
    {2,-1,-3}		// look straight down

//	{-1,2,3},
//	{1,2,-3}
};

// s = [0]/[2], t = [1]/[2]
int	vec_to_st[6][3] =
{
    {-2,3,1},
    {2,3,-1},

    {1,3,2},
    {-1,3,-2},

    {-2,-1,3},
    {-2,1,-3}

//	{-1,2,3},
//	{1,2,-3}
};

float	skymins[2][6], skymaxs[2][6];

void DrawSkyPolygon (int nump, vec3_t vecs)
{
    int		i,j;
    vec3_t	v, av;
    float	s, t, dv;
    int		axis;
    float	*vp;

    // decide which face it maps to
    VectorCopy (vec3_origin, v);
    for (i=0, vp=vecs ; i<nump ; i++, vp+=3)
    {
        VectorAdd (vp, v, v);
    }
    av[0] = fabs(v[0]);
    av[1] = fabs(v[1]);
    av[2] = fabs(v[2]);
    if (av[0] > av[1] && av[0] > av[2])
    {
        if (v[0] < 0)
            axis = 1;
        else
            axis = 0;
    }
    else if (av[1] > av[2] && av[1] > av[0])
    {
        if (v[1] < 0)
            axis = 3;
        else
            axis = 2;
    }
    else
    {
        if (v[2] < 0)
            axis = 5;
        else
            axis = 4;
    }

    // project new texture coords
    for (i=0 ; i<nump ; i++, vecs+=3)
    {
        j = vec_to_st[axis][2];
        if (j > 0)
            dv = vecs[j - 1];
        else
            dv = -vecs[-j - 1];

        j = vec_to_st[axis][0];
        if (j < 0)
            s = -vecs[-j -1] / dv;
        else
            s = vecs[j-1] / dv;
        j = vec_to_st[axis][1];
        if (j < 0)
            t = -vecs[-j -1] / dv;
        else
            t = vecs[j-1] / dv;

        if (s < skymins[0][axis])
            skymins[0][axis] = s;
        if (t < skymins[1][axis])
            skymins[1][axis] = t;
        if (s > skymaxs[0][axis])
            skymaxs[0][axis] = s;
        if (t > skymaxs[1][axis])
            skymaxs[1][axis] = t;
    }
}

#define	MAX_CLIP_VERTS	64
void ClipSkyPolygon (int nump, vec3_t vecs, int stage)
{
    float	*norm;
    float	*v;
    qboolean	front, back;
    float	d, e;
    float	dists[MAX_CLIP_VERTS];
    int		sides[MAX_CLIP_VERTS];
    vec3_t	newv[2][MAX_CLIP_VERTS];
    int		newc[2];
    int		i, j;

    if (nump > MAX_CLIP_VERTS-2)
        Sys_Error ("ClipSkyPolygon: MAX_CLIP_VERTS");
    if (stage == 6)
    {
        // fully clipped, so draw it
        DrawSkyPolygon (nump, vecs);
        return;
    }
    front = back = false;
    norm = skyclip[stage];

    for (i=0, v = vecs ; i<nump ; i++, v+=3)
    {
        d = DotProduct (v, norm);
        if (d > ON_EPSILON)
        {
            front = true;
            sides[i] = SIDE_FRONT;
        }
        else if (d < ON_EPSILON)
        {
            back = true;
            sides[i] = SIDE_BACK;
        }
        else
            sides[i] = SIDE_ON;
        dists[i] = d;
    }

    if (!front || !back)
    {
        // not clipped
        ClipSkyPolygon (nump, vecs, stage+1);
        return;
    }

    // clip it
    sides[i] = sides[0];
    dists[i] = dists[0];
    VectorCopy (vecs, (vecs+(i * 3)));
    newc[0] = newc[1] = 0;

    for (i=0, v = vecs ; i<nump ; i++, v+=3)
    {
        switch (sides[i])
        {
        case SIDE_FRONT:
            VectorCopy (v, newv[0][newc[0]]);
            newc[0]++;
            break;
        case SIDE_BACK:
            VectorCopy (v, newv[1][newc[1]]);
            newc[1]++;
            break;
        case SIDE_ON:
            VectorCopy (v, newv[0][newc[0]]);
            newc[0]++;
            VectorCopy (v, newv[1][newc[1]]);
            newc[1]++;
            break;
        default:
            break;
        }

        if (sides[i] == SIDE_ON || sides[i+1] == SIDE_ON || sides[i+1] == sides[i]) continue;

        d = dists[i] / (dists[i] - dists[i+1]);

        for (j=0 ; j<3 ; j++)
        {
            e = v[j] + d*(v[j+3] - v[j]);
            newv[0][newc[0]][j] = e;
            newv[1][newc[1]][j] = e;
        }
        newc[0]++;
        newc[1]++;
    }

    // continue
    ClipSkyPolygon (newc[0], newv[0][0], stage+1);
    ClipSkyPolygon (newc[1], newv[1][0], stage+1);
}

/*
=================
R_DrawSkyChain
=================
*/
void R_DrawSkyChain (msurface_t *s)
{
    msurface_t	*fa;
    int		    i;
    vec3_t	    verts[MAX_CLIP_VERTS];
    glpoly_t	*p;
    float		*v;

    glColor3f(1, 1, 1);

    GL_Bind(solidskytexture);

    // calculate vertex values for sky box
    for (fa=s ; fa ; fa=fa->texturechain)
    {
        for (p=fa->polys ; p ; p=p->next)
        {
            for (i=0, v = (float *)(&globalVertexTable[p->firstvertex]) ; i<p->numverts ; i++, v+=VERTEXSIZE)
            {
                VectorSubtract (v, r_origin, verts[i]);
            }
            ClipSkyPolygon (p->numverts, v, 0);
        }
    }
}

/*
==============
R_ClearSkyBox
==============
*/
void R_ClearSkyBox (void)
{
    int		i;

    for (i=0 ; i<6 ; i++)
    {
        skymins[0][i] = skymins[1][i] = 9999;
        skymaxs[0][i] = skymaxs[1][i] = -9999;
    }
}

void MakeSkyVec (float s, float t, int axis)
{
    vec3_t		v, b;
    int			j, k;

    b[0] = s*1024;
    b[1] = t*1024;
    b[2] = 1024;

    for (j=0 ; j<3 ; j++)
    {
        k = st_to_vec[axis][j];
        if (k < 0)
            v[j] = -b[-k - 1];
        else
            v[j] = b[k - 1];
        v[j] += r_origin[j];
    }

    // avoid bilerp seam
    s = (s+1)*0.5;
    t = (t+1)*0.5;

    if (s < 1.0/512)
        s = 1.0/512;
    else if (s > 511.0/512)
        s = 511.0/512;
    if (t < 1.0/512)
        t = 1.0/512;
    else if (t > 511.0/512)
        t = 511.0/512;

    t = 1.0 - t;
    glTexCoord2f (s, t);
    glVertex3fv (v);
}

/*
==============
R_DrawSkyBox
==============
*/
int	skytexorder[6] = {0,2,1,3,4,5};
void R_DrawSkyBox (void)
{
    int	i;

    if (gl_wireframe.value) return;

    if (skytexturenum >= 0)
    {
        if (!cl.worldmodel->textures[skytexturenum]->texturechain) return;
        cl.worldmodel->textures[skytexturenum]->texturechain = NULL;
    }
    glDepthMask (GL_FALSE);

    if (fog_enabled.value && !gl_wireframe.value)
    {
        glDisable(GL_FOG);
    }

    for (i=0 ; i<6 ; i++)
    {
        GL_Bind (SKY_TEX+skytexorder[i]);

        skymins[0][i] = -1;
        skymins[1][i] = -1;
        skymaxs[0][i] = 1;
        skymaxs[1][i] = 1;

        glBegin (GL_QUADS);
        MakeSkyVec (skymins[0][i], skymins[1][i], i);
        MakeSkyVec (skymins[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymins[1][i], i);
        glEnd ();
    }

    if (fog_enabled.value && !gl_wireframe.value)
    {
        glEnable(GL_FOG);
    }

    if (!skybox_hasclouds)
    {
        glDepthMask (GL_TRUE);
        return;
    }
    GL_Bind (SKY_TEX+6);

    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_COLOR);

    glMatrixMode(GL_TEXTURE);
    glPushMatrix();
    glTranslatef(cl.time*skybox_cloudspeed,0,0);
    glColor4ub(255,255,255,255);
    glBegin(GL_TRIANGLE_FAN);
    glTexCoord2f(0,0);
    glVertex3f(-800.0 + r_origin[0], -800.0 + r_origin[1], 20.0 + r_origin[2]);

    glTexCoord2f(0,40);
    glVertex3f(800.0 + r_origin[0], -800.0 + r_origin[1], 20.0 + r_origin[2]);

    glTexCoord2f(40,40);
    glVertex3f(800.0 + r_origin[0], 800.0 + r_origin[1], 20.0 + r_origin[2]);

    glTexCoord2f(40,0);
    glVertex3f(-800.0 + r_origin[0], 800.0 + r_origin[1], 20.0 + r_origin[2]);

    glEnd();
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);

    glDisable(GL_ALPHA_TEST);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

    for (i=0 ; i<6 ; i++)
    {
        GL_Bind (SKY_TEX+skytexorder[i]);

        skymins[0][i] = -1;
        skymins[1][i] = -1;
        skymaxs[0][i] = 1;
        skymaxs[1][i] = 1;

        glBegin (GL_QUADS);
        MakeSkyVec (skymins[0][i], skymins[1][i], i);
        MakeSkyVec (skymins[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymins[1][i], i);
        glEnd ();
    }
    glDisable(GL_BLEND);
    glDepthMask (GL_TRUE);
}

//===============================================================

/*
=============
R_InitSky

A sky texture is 256*128, with the right side being a masked overlay
==============
*/
void R_InitSky (texture_t *mt)
{
    int		    i, j, p;
    int			div;
    byte		*src;
    unsigned	topalpha;
    unsigned	*trans;
    unsigned	transpix;
    int		    r, g, b;
    unsigned	*rgba;

    // initialize our pointers
    trans = malloc (128 * 128 * 4);

    src = (byte *)mt + mt->offsets[0];

    // make an average value for the back to avoid
    // a fringe on the top level
    r = g = b = 0;

    for (i=0 ; i<128 ; i++)
    {
        for (j=0 ; j<128 ; j++)
        {
            p = src[i*256 + j + 128];
            rgba = &d_8to24table[p];
            trans[(i * 128) + j] = *rgba;

            r += ((byte *)rgba)[0];
            g += ((byte *)rgba)[1];
            b += ((byte *)rgba)[2];
        }
    }
    ((byte *)&transpix)[0] = r / (128 * 128);
    ((byte *)&transpix)[1] = g / (128 * 128);
    ((byte *)&transpix)[2] = b / (128 * 128);
    ((byte *)&transpix)[3] = 0;

    // get another average cos the bottom layer average can be too dark
    div = r = g = b = 0;

    if (!solidskytexture)
    {
        solidskytexture = texture_extension_number++;
    }
    GL_Bind (solidskytexture );

    glTexImage2D (GL_TEXTURE_2D, 0, gl_solid_format, 128, 128, 0, GL_RGBA, GL_UNSIGNED_BYTE, trans);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    for (i=0 ; i<128 ; i++)
    {
        for (j=0 ; j<128 ; j++)
        {
            p = src[i * 256 + j];

            if (p == 0)
            {
                topalpha = transpix;
            }
            else
            {
                rgba = &d_8to24table[p];

                g += ((byte *) rgba)[1];
                r += ((byte *) rgba)[0];
                b += ((byte *) rgba)[2];

                div++;

                topalpha = d_8to24table[p];
            }
            ((byte *) &topalpha)[3] = ((byte *) &topalpha)[3] / 2;

            trans[(i * 128) + j] = topalpha;
        }
    }

    if (!alphaskytexture)
    {
        alphaskytexture = texture_extension_number++;
    }
    GL_Bind(alphaskytexture);

    glTexImage2D (GL_TEXTURE_2D, 0, gl_alpha_format, 128, 128, 0, GL_RGBA, GL_UNSIGNED_BYTE, trans);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    // free the used memory
    free (trans);
}

